Alarm control



March 6, 1934. D. w. DAVIS 1,950,022

ALARM CONTROL Filed April 11, 1932 J- w I P In vemo r Dean W Dav/'6,

A I iorneya.

Patented Mar. 6, 1934 UNITED STATES ALARM CONTROL Dean W. Davis, Pendleton, Ind., assignor of onehalf to Gustav A. Schnull, Indianapolis, Ind.

Application April 11, 1932, Serial No. 604,600

3 Claim.

This invention relates to the art of alarm operating devices such as may be employed to give an alarm of a burglary or of fire and has for one of its primary objects the provision of an 5 operating device wherein a closed electrical circuit may be employed to have a part thereof in the zone being protected whereby any break in that circuit will render the alarm device operative.

A further important object of the invention is to provide a very low current consuming device in which dry cells may be employed in the closed circuit to supply current therein over a long period of time before renewal is required so that current from power lines or building circuits need not be depended upon.

A still further important object of the invention is to provide means for operating an alarm to be set in operation by the weight of a solenoid armature as released upon interruption of current flow in the solenoid winding. These and other objects and advantages will become apparent in the following description of the invention as illustrated more or less diagrammatically by the accompanying drawing, in which Fig. 1 is a diagrammatic plan of a complete electric alarm system;

Fig. 2, a fragmentary vertical section of a system having a mechanically operated signal;

Fig. 3, a diiferent form of the alarm control in diagram; and

Fig. 4, a fragmentary elevation of the solenoid armature as employed in the form in Fig. 3.

Like characters of reference indicate like parts in the several views of the drawing.

Referring first to the form as illustrated in Fig. 1, I mount a solenoid magnet 10 in a vertically disposed position whereby the armature 11 may be free to drop vertically when there is no current flow in the winding of the magnet 10. Between the terminals of the magnet, I provide a closed circuit including a battery 12 of one or more dry cells and the line 13. This line 13 is preferably made of very fine wire such as No. 40 (B. & S. gauge) and is strung through the zone to be protected in such manner that it may become bro-ken by intruders or melted by fire. Preferably no switches are provided in this circuit so that they may not accidentally be left open. The current supplied by the battery 12 is kept at a minimum and only sufficient current is employed that will just hold the armature 11 in a retracted or up position. This current is .of such low amount, that once the armature has dropped upon interruption of the current flow,

restoring of the current flow will not pull the armature back up within the solenoid coil.

A lever 14 is pivotally mounted below the magnet 10 to have an arm normally extend horizontally across immediately below the lower end of the armature 11 when in the retracted position. This lever 14 has a leg 20 extending downward, on the forward side of which is a notch within which the free end of a leaf spring 15 may rest to press downwardly against the lower side of the notch without a tendency to rock the lever. The lever is balanced, here shown by a sliding weight 16, so as to maintain the arm in the horizontal position.

An electric bell 17 is provided as a signal and is in a circuit including a battery 18 as a source of operating current, the spring 15, and a contact point 19, the ci cuit being normally open between the spring and the contact point. If for any reason the line 13 should become broken or the battery 12 fail, current would no longer be supplied to the magnet 10 and the armature normally therein would be released todrop down onto the arm of the lever 14 so as to rock it downwardly as indicated by the dash lines. As the lever 14 is thus rocked the leg 20 is rocked back away from the end of the spring 15 to release the spring from engagement in the notch in the leg. The released spring drops against the contact point 19 and thus closes the circuit including the bell 17 which then continues to operate until the battery 18 is exhausted or the circuit again interrupted by resetting the spring in the notch of the lever 14, but this resetting can only be accomplished by restoring current to the magnet 10 to hold up the armature 11 when it is pushed back within the magnet.

In the form shown in Fig. 2, I employ the solenoid magnet 10 with the external closed circuit wire 13, and the battery 12, here shown as being carried in the depending metallic tube 34 which is in electric circuit through the frame 21 with one of the terminals 22 of the magnet 10. The other terminal of the coil is connected with the binding post 23 from which the line 13 leads back to the other post 24, which in turn is connected through the spring 25 to the battery 12. A mechanically operated bell or gong 25 is mounted on the frame 21 to have a shaft or button 26 extending from the bell mechanism to within the frame. This bell is of the common type, spring operated, as is employed for door bells and the like and its construction is well known to those versed in the art and its details do not enter into the invention. Horizontal pressure backward on the button 26 releases the spring mechanism to set it in operation to strike the bell. I pivotally mount a bell crank lever 27 to have a downturned arm normally hang in front of the button 26 and a horizontally disposed arm across under the raised armature 11, but at a distance therebelow. At the outer end of this horizontal arm, I rockably attach a latch bar 28 having a hooked end adapted to rest over a pin 29. From the inner side of the bar 28, extends a leg 30 to immediately under the lower end of the raised armature 11, and from the outer side, a counterweight arm 31 of just enough weight to overcome the weight of the leg 30 and tip the latch bar toward the pin. A spring 32 is engaged to the horizontal arm of the lever 27 tending to throw the vertical arm backwardly against the button 26, which action is prevented as long as the latch bar 23 hooked over the pin 29. When the circuit is broken including the magnet 10, the armature 11 drops to strike the leg 30 to rock the latch bar 28 back from the pin 29 to have the spring jerk the lever 27 around to press back on the button 26 and thus operate the bell 25. A lever 33 is provided to reset the lever 27 when current flow is again restored in the magnet circuit so as to support the armature 11 in the retracted position.

In either of the forms shown in Figs. 1 and 2, the weight of the armature 11 must be sufficient to rock the lever 14 or the leg 30, so that, upon resetting the alarm control with no current flowing in the magnet winding, the armature would not rest on the lever or leg without rocking it. The form shown in Figs. 3 and 4 eliminates the possibility of resetting the alarm shut-01f without the armature being retained by the magnet.

In this form as indicated in Figs. 3 and 4, the winding 10 is provided with a tube 35 within which the armature 36 may freely slide. The tube extends below the winding 10 a distance and a rod 37 is screw-threadedly engaged in the armature 36 to extend downward centrally of the tube and to extend from the bottom thereof. A short cylinder 38 of non-magnetic material is axially threaded over the rod 37 to be free to slide up and down thereon and also to be free to slide freely within the tube 35. A nut 39 screwthreadedly engages the lower end of the rod 37 to serve as a stop, between the limits of which stop and the under end of the armature 36, the cylinder 38 may be raised and lowered, the cylinder normally resting on the nut 39.

The tube 35 is provided with a side opening below the winding 10, through which opening a tongue 40 on the upper end of the arm 41 is normally inserted by the spring 42 pressing on the arm. A reset lever 43 is rockably mounted adjacent the tube 35 to have an end to be in the path of the lower end of the rod 37 when in its lowermost position. By rocking the lever 43, the rod 37 may be pushed back up within the tube to carry the armature 36 back to the extreme upper end of the tube within the winding 10 where the armature will be held if there be current supplied to the winding from the battery 12 through the line 13. When the armature 36 is in the down position as indicated by the dotted lines to have its lower end on top of the tongue 40, the tongue extends to within the tube, and when the armature is raised, the tongue is pressed out again as the cylinder is carried on up to its upper position as determined by the nut 39. The spring 42 exerts but comparatively small pressure against the arm 41 so that either the armature or cylinder may be shifted easily although the tongue 40 may be pressing laterally thereagainst.

The lower end of the arm 41 is rockably supported and has a foot 44 which extends laterally to be in the path of some signal actuating means, here shown as an escapement wheel 44 which is spring actuated to sound a bell 45. Upon rocking of the arm 41 toward the tube 35 as the tongue 46 enters between the armature and cylinder, the foot 44 is raised to release the escapement wheel and cause the bell to be tapped. Reverse rocking of the arm causes the foot 44 to intercept the wheel and stop its rotation.

Assuming the line 13 to be closed and the armature 36 raised and held by the magnetic action within the coil 10, and then supposing the line 13 to be broken, the armature 36 will drop to push the rod 37 on down through the cylinder 38 to lower the cylinder supporting nut 39. The cylinder is preferably heavy enough to drop of its own weight, but if it should hang in place, the heavier armature 36 above will drop against it and drive it on down Within the tube past the tongue 40. The upper end of the cylinder and the lower end of the armature are both bevelled so that as the tongue cylinder slides out from under the tongue, the tongue presses into the groove formed by the two bevels between the armature and cylinder and passes on under the armature as the cylinder drops on down. The entrance of the tongue 40 to under the armature thus permit the spring 42 to rock the arm 41 so as to lift the foot 44 and allow the signal to sound.

When the device is to be reset, the lever 43 is pressed down on its outer end to lift the cylinder 38 to force out the tongue 40, but if the current flow through the winding 10 be not sufficient, then the armature 36 drops back to rest on the cylinder 38 to cause it to drop also, whereby it becomes impossible to reset unless the proper current flow is restored in the line 13. If the battery 12 becomes weak so that the armature can no longer be held up, then it drops to set off the alarm.

Thus the closed circuit method of normally maintaining an alarm system may be applied to either an electrically or a mechanically operated signal operated by current or a force independent of the current supply to the closed trigger circuit. While I have here shown my invention in the form as best known to me it is obvious that structural changes may be made therein, such as the signal operating means as actuated by the armature, without departing from the spirit of the invention, and I therefore do not desire to be limited to that precise form beyond the limitations as may be imposed by the following claims.

I claim:

1. An alarm device comprising in combination an electro-magnet having an armature, a closed circuit including said magnet and extending into a protected zone, a signal mechanism, an operating lever for setting the signal mechanism into I 1 operation including means for biasing it into position to operate said mechanism, means for normally holding said lever in non-operating position including a second lever, a supporting pin therefor, means for balancing the lever about the pin and connections between said first and second levers so located as to set up a zero rocking force on said second lever, the armature of said magnet being so located with respect to said sec' ond lever that when the magnet is deenergized the armature will fall on the second lever to overbalance it and release the operating lever to set oii the alarm.

2. An alarm device comprising a solenoid magnet, a battery of relatively low current supply, a severable line carried through a guarded zone, the winding of said magnet, said battery and said line being connected in series to fOliil a closed circuit of relatively high resistance, an armature normally held in a vertically elevated position by the magnet by flow of current from said battery, an alarm signal having an operating member, a lever having an end extending under said armature, a lever supporting pin, hook means on said lever cooperating with said pin whereby said lever is normally carried by the pin and is released from the pin on rocking of said lever, a second lever having one arm pivotally engaging the first lever by one end immediately below said pin, pivot means for said second lever positioned so that no rocking of the first lever about the pin by the second lever is set up and the other end of said second lever being adjacent said operating member, and a spring normally tending to rock said first arm downwardly to pull said first lever against said pin whereby upon breaking of said circuit to deenergize said magnet, the armature thereof will drop against said first lever to rock it out of engagement with said pin and thereby permit said spring to swing the second lever against said operating member.

3. An alarm device comprising in combination an electromagnet having an armature, a closed circuit including said magn t and extending into a protected zone, a signal mechanism comprising an electricaliy operated sounding device and a normally open circuit including the device, said armature being normally supported by the magnet in a raised position, an operating lever comsing a spring nieinber normally biased to a position closing contacts in said signal open circult, a second lever having one end extending under said armature, a supporting pin therefor, means for balancing the second lever, and a member extending from the second lever having a releasable connection with said first lever so located as to set up a zero rocking force by the first lever on the second lever, said armature being located with respect to said second lever that when the magnet is deenergized, the armature will fall against the second lever to overbalance it and release the first lever to close the signal circuit to set ofi the alarm.

DEAN W. DAVIS. 

